Anti-seeding arrangement

ABSTRACT

The present invention relates to an anti-seeding arrangement ( 100 ) for invasive treatment of a human or animal body comprising an elongated hollow member ( 102 ), and a first electrode ( 116 ) of which one portion is arranged near one end of the elongated hollow member ( 102 ), said first electrode ( 116 ) being connectable to an electromagnetic field generator ( 110 ), wherein the elongated hollow member ( 102 ) is arranged to be inserted into the human or animal body, control means ( 106, 108 ) arranged to control the electromagnetic field generator ( 110 ) for delivering radio frequency bursts to the first electrode ( 116 ), and sensing means ( 104 ) to sense a physical property dependent on the insertion length of the elongated hollow member ( 102 ) in the human or animal body, and wherein the control means ( 106, 108 ) is arranged to control the operation of the electromagnetic field generator ( 110 ) in dependence of the sensed physical property.

The present invention relates in general to providing an arrangement forinvasive operations in human or animal bodies, and especially toproviding an arrangement for anti-seeding in connection to invasiveoperations in human or animal bodies.

DESCRIPTION OF RELATED ART

Many people in the western world face the prospect of cancer. The mostcommon cancer forms in females and males are breast cancer and prostaticcancer, respectively.

A successful cancer therapy is often dependent on a high quality tumourdiagnosis. There are today two major methods of morphological diagnosis.These are histopathological examination of surgical biopsies or corebiopsies and cytopathological examination of fine needle aspirates.

In core biopsy, a tissue sample is removed from the lesion, for exampleby using a coarse core biopsy needle. This tissue sample is thenexamined histologically.

In cytological diagnosis, a suspension of cells is aspirated from thelesion with the aid of a fine needle. Since the adhesion between tumourcells is lower than the adhesion between healthy cells, tumour cells areenriched in the aspirate. Ongoing advances suggest that completelyobjective molecular diagnostic procedures on single cells from fineneedle aspirates can be available in the near future.

Applying modern diagnosis, small tumours can be detected which have notyet metastased. For such cancer tumours, having an extension thattypically is less than 10 mm, conventional surgery may be seen as toocoarse a method.

Also, in therapy the tendency has been towards less invasive localtreatment of the tumour and hence away from radical surgery such asmastectomy, in the breast cancer case. The goal of radical mastectomy isto remove all malignant tissue, which combined with lymph noderesection, often results in considerable hospitalisation.

Minimally invasive approaches, in contrast to open surgery, have aspotential benefits reduced morbidity rates, reduced treatment durationand provide the possibility to treat a patient in a weak medicalcondition.

One example of a minimally invasive therapy approach is the radiofrequency ablation (RFA) technique which uses radio frequency energy tocause thermal destruction of tumour cells. The destruction can beobtained by, for example, inserting a needle directly in the tumour,arranging a large counter electrode to an outer surface of the body andapplying radio frequency energy between the needle and the counterelectrode. The high current density at the needle generates heat in thetissue, causing thermal destruction and/or denaturation of said tissue.

At present the RFA technique is most often viewed as being palliativeand used to shrink the tumours such that surgery can be avoided.

Another minimally invasive approach is stereo tactic excision or largecore biopsy, which is a surgical technique that preferably involvesremoving the entire breast lesion under image guidance. By using largecore biopsy, breast tissue of the size of 5 mm to 20 mm may be removed.This procedure also allows the radiologist or surgeon to remove theentire lesion in one non-fragmented piece. The core specimen of thebreast tissue is often removed with a looped wire and taken to thepathology laboratory for diagnosis.

Yet another minimally invasive approach that can be applied in diagnosisand therapy of body tissue is infusion of diagnostic and therapeuticagents to a site within a tissue. By inserting a needle reaching aninvasive site, and presenting the needle tip to the tissue site, asite-specific delivery of diagnostic and therapeutic agents to saidtissue site is enabled.

Yet other minimally invasive techniques that may be used for the same orsimilar purposes are endoscopic procedures, wherein tubular devices arepercutaneously inserted in a body to reach an invasive site in need forsurgical operation or investigation. In short, tissue may hence beresected, visually examined and sampled without open surgery.

The techniques and methods for diagnosis and/or therapy of tissue asmentioned above have the common denominator of involving a touching orpuncturing malignant tissue by at least one part of the device beingused.

In addition, said techniques and methods may also touch or puncturelocal infections.

By puncturing and/or manipulating malignant tissue, cancer cells can bedisrupted from their original position and deposed in other places.

Disruption and disposition of cancer cells may further give rise toseeding of cancer cells in the tract formed by the equipment being used,considered that some part, for instance the distal end of a needle, ofthe equipment penetrates or contacts the malignant tissue. Uponpenetration or contacting by the distal end of malignant tissue, saiddistal end becomes contaminated with non-healthy cells. Upon removal ofthe equipment, the contaminated distal end is slid along thetract/channel that was formed upon insertion, malignant tissue cells maycome loose from the contaminated distal end or the malignant tissue assuch and may be repositioned onto the walls of the tract/channel,thereby causing the seeding of the tumour.

This seeding of cancer cells may give rise to new cancer tumours.

Tumour seeding may thus be result of core biopsy, laparoscopy, radiofrequency ablation, injection, and fine needle aspiration or punctuationetc. and can therefore negate the benefits of the operation involved.

For obvious reasons, seeding of local infectious matter may also occurduring the above operations. This is of special importance duringtrans-rectal procedures of for example the prostate.

In the following, prior art documents related to potential spread ofun-healthy cells are presented.

From US 2004/0186422 A1 a needle for delivering therapeutic ordiagnostic agents in a target site in a body is known. The needle may beprovided with an electrode that is coupled to a radio frequencygenerator. By delivering electrical energy from at least a portion ofthe needle to tissue surrounding at least a portion of the tract, thesurrounding tissue may coagulate, be ablated or otherwise treat thesurrounding tissue to substantially seal or occlude the tract.Electrical energy may be delivered to additional tissue along the tractin short bursts such that spaced-apart regions can be treated.Alternatively, energy is delivered substantially continuously uponwithdrawal of the needle to substantially seal the tract along itsentire length. The tract may thus be substantially sealed lowering therisk of tracking seeding from a tumour and/or contaminating tissuesurrounding a target region to which an agent is delivered.

One disadvantageous property of this technique is that the deliveredradio frequency energy heats the tissue surrounding the track such thattissue of a relatively large depth is affected by the high temperatureproduced.

Another disadvantage of the diagnostic equipment of this technique isthat sample tissue in the needle is also affected by the heating causedby the radio frequency energy.

A potential disadvantage of the technique of US 2004/0186422 A1 isassociated with the application of the short bursts or continuous radiofrequency energy to substantially seal the track when the needle orinstrument is being retracted. Since the technique is operated manuallyand the needle is typically held and retracted by an operator, there isa risk that viable cells will remain in the track after the applicationof the radio frequency energy when retracting the needle, since theresult of treating the tract is dependent of the skill of the operatorusing this technique.

Another potential disadvantage with the regime of US 2004/0186422 A1 isthere is no solution to disruption of tumour cells when the insertedinstrument penetrates through the tumour, potentially leading to seedingof tumour cells.

In addition, since the technique is operated manually, the technique istime consuming in general and consumes time for an operator inparticular, which are disadvantageous.

From US 2003/0195500 it is known a modular biopsy ablation or trackcoagulation needle comprising an outer tubular member and an innermember which allows a biopsy needle to be inserted into, and coaxiallyengaged with, a delivery needle and removed when not needed. It alsoallows to more efficiently biopsy a tumour, ablate it and coagulate thetrack by ablation while reducing the track seeding and blood loss. Theablation needle and biopsy needle forms a connector arranged to becoupled to an electric ablating source.

In the case of track ablation, an isotherm of 48° C. is suggested whichextends 1 mm radially from the track into the tissue. In the case oftumour ablation the isotherm of 48° C. is suggested to have a radicalextension of 20 mm, which is being achieved by using a higher microwavepower or a different microwave frequency, as compared to the trackablation case.

A clear disadvantage with the technique as disclosed by US 2003/0195500is that this device uses microwave frequency energy. A consequence ofusing microwave frequencies is that a comparatively large tissue regionis heated, where said region also comprises healthy tissue in no need oftreatment, which clearly is non-beneficial.

Another disadvantage of the US 2003/0195500 technique is thatcoagulation of the entire track requires multiple applications ofmicro-wave energy, where the delivery needle is rejected piece-wise, andwhere microwave frequencies are applied to the delivery needle inbetween the rejections, due to the fact that each application of themicrowave energy of the power being used to achieve the isotherms asmentioned above, lasts a relatively long time.

Moreover, manual operation of this regime brings the disadvantage ofrisking that viable cells remain in the track subsequent to theapplication of micro-wave energy, since the tissue surrounding the trackis often non-homogenous and therefore require different applications ofenergy to ablate the track.

Yet another disadvantage is that energy absorption upon application ofmicrowave frequency is often non-homogenous, which can result in spotsbeing over-heated, so called “hot spots”.

From U.S. Pat. No. 6,126,216 it is known a medical instrument comprisinga cannula or probe that is used to penetrate tissue to a target area tobe used in medical procedures including biopsy and radio frequencyablation of undesirable tissues or cells for treatment of or to preventthe spread of cancer cells during a biopsy procedure.

The exterior surface of the probe has a dielectric coating, and controlmeans for adjusting the electric current to the cannula, a radiofrequency generator and a return electrode. By generating radiofrequency energy, the cannula is heated above a critical temperaturecausing the tissue surrounding the cannula to become non-viable.

The disclosure of U.S. Pat. No. 6,126,216 comprises a first applicationbeing a biopsy needle, for which ablative radio frequency energy isclaimed to be delivered to the tissue to provide resistive heatingapproximately 10 cell layers deep around the cannula. No information isprovided to support this cell layer performance.

One drawback with the biopsy needle technique as disclosed in U.S. Pat.No. 6,126,216 is the application of radio frequency energy which isapplied to achieve elevated temperature in tissue of a depth ofapproximately 10 cell layers.

To our understanding, the radio frequency energy is applied by applyinga current having a very low current density in order to restrict thetemperature rise to a depth of approximately 10 cell layers. Using a lowcurrent density however requires a long duration of application of theradio frequency energy, which for this reason is a clear drawback sincethe rise in temperature during that duration will be influenced by heatconduction to neighbouring tissues and thereby also by blood perfusionand other tissue properties.

Another drawback of the technique as disclosed by U.S. Pat. No.6,126,216 is the skin burn effect that is caused due to the contactbetween the electrode and the skin upon penetrating the skin by thebiopsy needle, upon application of radio frequency energy to the biopsyneedle. The usage of the entire shaft of the needle as an electrode thusresults in undesired skin burn effects.

A potential drawback of the technique of U.S. Pat. No. 6,126,216 is thatfull penetration of a tumour by the electrode may result in dislocatedviable tumour cells that could proliferate in healthy tissue into newcancer tumours.

Conclusively, a common disadvantage of the prior art techniques anddisclosures is that movement of inserted instruments in longitudinaldirections may result in non-complete track tumour cell killing.

In addition, continuous application of energy may result in anunnecessarily large diameter of tissue killing that the sample in theneedle is affected as well as an increased operation time.

There is thus a need for providing a more efficient anti-seeding devicefree from the disadvantages and drawbacks that are associated with theprior art techniques.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an anti-seedingarrangement enabling a complete anti-seeding treatment.

According to one aspect of this invention, this object is achieved bythe arrangement for invasive treatment of a human or animal bodycomprising

an elongated hollow member having two ends, and a first electrode ofwhich at least one portion is arranged at least near one end of theelongated hollow member, said first electrode being connectable to anelectromagnetic field generator, wherein the elongated hollow member isarranged to be at least partly inserted into the human or animal body,sensing means arranged to sense a physical property of the arrangement,which physical property is being dependent on at least of the insertionlength of the elongated hollow member in the human or animal body, andcontrol means arranged to control the electromagnetic field generatorfor delivering radio frequency bursts to the first electrode of theelongated hollow member, being connectable to an electromagnetic fieldgenerator, being arranged to control the operation of theelectromagnetic field generator in dependence of the sensed physicalproperty by the sensing means and comprising triggering means fortriggering the electromagnetic field generator to deliver radiofrequency bursts in dependence of variations of the sensed physicalproperty.

A second aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the sensing means is arranged to sense the physicalproperty optically, mechanically, acoustically, electrically orelectromagnetically.

A third aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the sensing means comprises impedance sensing means.

This aspect of the present invention is advantageous since the impedancebeing an electrical quantity that is easily obtainable and convenient toutilize in electrical or electronic control means.

A fifth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, further comprising a second electrode arranged to be connectedto the electromagnetic field generator and arranged to be positioned onthe human or animal body.

A sixth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the fifthaspect, wherein the impedance sensing means is arranged to sense animpedance at least related to the impedance between the second electrodeand at least part of the first electrode.

This aspect of the present invention is advantageous since the impedancebetween the second electrode and at least part of the first electrode iseasily measurable.

A seventh aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the sensing means is arranged to sense the distance froma reference point for the elongated hollow member to the surface of thetissue into which the elongated hollow member is arranged to be at leastpartly inserted.

An eighth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the control means is arranged to be connected to thesensing means.

A ninth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the control means is arranged to control the operationof the electromagnetic field generator such that radio frequency burstsare delivered from the electromagnetic field generator in dependence ofvariations of the sensed physical property value.

This aspect of the present invention is advantageous since making theelectromagnetic field generator deliver radio frequency energy independence of the variations of the sensed physical property enables arapid response to movements of the elongated hollow member.

A tenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the arrangement further comprises the electromagneticfield generator, and wherein the electromagnetic field generator isarranged to deliver radio frequency bursts.

An eleventh aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the first electrode is located at one end of theelongated hollow member.

A twelfth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member comprises a region that iselectrically insulated in relation to the first electrode.

This aspect of the present invention is advantageous since it providesprotection against skin burn effects upon operation of the arrangementof the present invention.

A thirteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the twelfthaspect, wherein the insulating region is situated near the other end ofthe elongated hollow member.

A fourteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of thethirteenth aspect, wherein the insulating region comprises a hollowinsulating sheath being longitudinally movable over the first electrode.

This aspect of the present invention is advantageous since theinsulating sheath enables quick variation of the effective length of thefirst electrode in the tissue.

A fifteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the first electrode is longitudinally segmented.

This aspect of the present invention is advantageous since segmentationmay provide protection against skin burn effects, as well as enablevariation of the effective length of the first electrode.

A sixteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member is coated with a dielectricmaterial.

This aspect of the present invention is advantageous since ablation bypart of an elongated hollow member may be achieved at one radiofrequency and anti-seeding of the entire track may be achieved using thesame elongated hollow member at a different frequency

A seventeenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of thesixteenth aspect, wherein the radio frequency bursts are generated atone or more radio frequencies.

An eighteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member comprises a needle arrangedfor fine needle aspiration or injection.

This aspect of the present invention is advantageous since it providesanti-seeding to fine aspiration or injection needles.

A nineteenth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member further comprises a solidmember insertable into the hollow member, wherein both are arranged forbiopsy operations.

This aspect of the present invention is advantageous since it providesanti-seeding to elongated hollow members used in biopsy operations.

A twentieth aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member is arranged for radiofrequency ablation of tissue of human or animal body.

This aspect of the present invention is advantageous since it providesanti-seeding to elongated hollow members used in ablation.

A twenty-first aspect of the present invention is directed towards thearrangement for invasive treatment including the features of the firstaspect, wherein the elongated hollow member is arranged for endoscopicoperations.

This aspect of the present invention is advantageous since it providesanti-seeding to elongated hollow members used for endoscopic operations.

The present invention has the following overall advantages:

Application of sensing means for the detection of movement of theelongated hollow member together with the usage of radio frequency powercreating an essentially instantaneous denaturation of tissue surroundingan anti-seeding electrode, provides a rapid arrangement for anti-seedingwithout being directed towards time consuming alternatives as presentedby the prior art. The invention is also advantageous since the rapidresponse will be dependent on the triggering of the electromagneticfield generator.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail in relationto the enclosed drawings, in which:

FIG. 1 shows a schematical representation of an arrangement for invasivetreatment according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention thus relates to an arrangement for treating ahuman or animal body in general, and to an arrangement for denaturatingtissue, cells and infectious matter in a human or animal body inparticular.

Since seeding or spreading of malignant cells, tissue or infectiousmatter is an evident risk when inserting medical equipment into a humanor animal body site containing such matter, seeding may occur in variousapplications such as infusion, radio frequency ablation, fine needleaspiration, core biopsy as well as endoscopic procedures. For thisreason and to enable a more efficient anti-seeding procedure theanti-seeding arrangement of the present invention is arranged to beutilized in every one of the applications as mentioned above, that is ininfusion, in radio frequency ablation, in fine needle aspiration, incore biopsy as well as in endoscopic procedures.

Whenever a member is passed through healthy tissue after the managementof infectious or malign tissue, it is desirable that the member is freefrom contamination

With this aim radio frequency bursts are applied between a firstelectrode and a counter electrode in the present invention.

In general terms the arrangement for anti-seeding according to thepresent invention comprises an elongated hollow member that is adaptedto be inserted into a tissue by puncturing the tissue with one end ofthe elongated hollow member.

In addition the arrangement comprises means for sensing longitudinalmovement of the member relative to the tissue. Moreover the arrangementalso comprises means for controlling an electromagnetic field generatorsuch that radio frequency bursts of a relatively high power can beapplied to the tissue by the elongated hollow member.

With reference to FIG. 1 schematically showing one representation of thearrangement for invasive treatment according to the present invention,the present invention will further be explained.

The representation in FIG. 1 of the arrangement 100 comprises anelongated hollow member 102, which may be adapted to specificapplications of this invention, as will be described down below andwhich further is arranged to be at least partially inserted in a humanor animal body. The arrangement 100 further comprises sensing means 104coupled to the elongated hollow member 102 and arranged to be used whendetermining the insertion length of the elongated hollow member 102 in ahuman or animal body, and a control unit 108 to which the sensing unit104 and a user input unit 112, are connected. The control unit 108 isfurther connected to a triggering unit 106 and a radio frequencygenerator 110, where the triggering unit 106 is arranged to trigger theradio frequency generator 110 in dependence of input from the sensingunit 104 and the user input unit 112. The radio frequency generator 110is further coupled to a first electrode 116 that is comprised by theelongated hollow member 102, and to a counter electrode 114, being oneexample of a second electrode.

The sensing unit 104 may be arranged to sense the impedance between thefirst electrode 116 of the elongated hollow member 102 and the counterplate 114, wherein the impedance is dependent of the insertion length ofthe elongated hollow member in the human or animal body. The impedancebetween the first electrode of the elongated hollow member and thecounter plate typically decreases upon increasing the penetration depthin the human or animal body. This is due to that the contact surfacebetween the first electrode and the surrounding tissue when penetratingthe elongated hollow member is increased.

In an alternative embodiment of the present invention, the sensing unit104 is arranged to sense the penetration depth of the elongated hollowmember in the tissue, for instance the distance from a reference pointfor the elongated hollow member to the tissue surface, in a mechanicalway.

In yet another embodiment of the present invention, the sensing unit 104may be arranged to sense the penetration depth of the elongated hollowmember in the tissue acoustically or electromagnetically, for instanceby sensing the distance from a reference point for the elongated tubularmember to the tissue surface.

According to still yet another embodiment of the present invention thesensing means and the control means may be integrally formed.

It should be emphasized that the arrangement as schematically shown inFIG. 1 is one representation of an arrangement of the present invention.Other representations which may comprise different units, and/orcomprise units having combined functions as compared with therepresentation as shown in FIG. 1, are also envisaged.

The triggering unit 106 is thus arranged to be connected to the radiofrequency generator 110 and to generate a trigger signal triggering theradio frequency generator to generate radio frequency energy. Moreover,the radio frequency generator 110 is arranged to generate radiofrequency energy in the form of bursts having a duration of the ordermicroseconds up to milliseconds depending on the used frequency in thebursts. The radio frequency generator is arranged to deliver such burstsat regular intervals having an off-duration of several orders ofmagnitude larger than the on-duration, wherein the on-duration equals tothe burst length.

For this reason a relatively high power of radio frequency energy may beapplied for the purpose of anti-seeding. The power that is applicable ineach case is dependent on a number of parameters including the diameterof the elongated hollow member to be inserted in the tissue, theconductivity and characteristics of the tissue into which the member isto be inserted, the blood flow of the tissue, the shape andconfiguration of the electrode of the elongated hollow member etc.

Since the power dependency of the radius, R of an electrode isproportional to R⁴, large electrodes require a high power, whereasanti-seeding using thin electrodes shows promising results using low ormoderate power levels.

It is however possible to use high power radio frequency energy undercertain circumstances, as indicated above. For instance peak powerlevels up to tens of kW may be used. Again by using an off-durationbeing several orders of magnitude larger than the on-duration, highpower levels may be used in special circumstances. In general moremodest power levels tailored for the case in point are used with whichrapid highly efficient anti-seeding may be obtained.

The triggering unit 106 may be arranged to trigger the electromagneticgenerator 110 to deliver electromagnetic energy to the first electrode,as the sensing unit senses a movement of the elongated hollow member102. The elongated hollow member is either retracted manually ormechanically or may even be moved by a combined motion under both manualand mechanical influence. The electromagnetic energy can be delivered tothe first electrode irrespective of how the elongated hollow member isretracted.

The radio frequency bursts as applied to the first electrode may thus beactivated upon retraction of the elongated hollow member 102. In onealternative embodiment of the present invention the radio frequencybursts may be activated upon insertion of the elongated hollow member inthe human or animal body.

Application of bursts or short pulses when using the arrangement 100 inrelation to a lesion in a human or an animal body, enables the controlof the application of radio frequency energy to the tissue such that thetissue region that is affected by radio frequency energy is a few celllayers thick around the first electrode 116.

Moreover, using sensing means for the control of the application of highpower short pulses achieves substantially immediate tract killingenabling rapid movement of elongated hollow members 102 in the treatedtissue, with unchanged anti-seeding performance.

Rapid and reliable tract killing or denaturation of a tissue site underinvestigation is thus enabled by using an elongated hollow member of thepresent invention and triggering of radio frequency bursts oranti-seeding pulses.

In one alternative embodiment of the present invention, the arrangement100 may comprise means for longitudinal and/or rotational movements ofthe elongated hollow member. Such means may provide an oscillatinglongitudinal vibration and/or rotational movement of the elongatedhollow member, wherein the movement has a frequency in the order of50-500 Hz. Providing an oscillating longitudinal and/or rotationalmovement of the elongated hollow member 102 facilitates insertion of theelongated hollow member in the human or animal body as penetrationresistance of the needle into the tumour during the insertion phase isdecreased. It may also increase the sample volume.

Triggered anti-seeding is thus also needed during each vibrationalretraction and insertion phase.

In addition to the advantage of denaturation possible cancer cells inthe track caused upon insertion of the elongated hollow member,application of radio frequency energy brings the advantage of stoppingpotential bleeding from the lesion caused by the elongated hollowmember.

In the following will the elongated hollow member be explained in moredetail.

The elongated hollow member 102 typically has first and a second end.Upon usage of the elongated hollow member 102, that is for instanceinserting the elongated hollow member in a human or animal body, theseends can be denoted the proximal end and a distal end, respectively.Moreover the first electrode may be arranged at the distal end of theelongated hollow member 102, according to one embodiment of the presentinvention. According to another embodiment of the present invention thefirst electrode is arranged near the distal end of the elongated hollowmember 102. According to yet another embodiment of the presentinvention, the first electrode may be arranged at another position alongthe elongated hollow member 102.

According to yet another embodiment of the present invention the firstelectrode is arranged along the elongated hollow member in a way suchthat the first electrode 116 possesses a longitudinal extension, alongthe elongated hollow member 102.

According to one embodiment of the present invention the elongatedhollow member 102 is arranged to be connected to the radio frequencygenerator 110, such that the first electrode 116 of the elongated hollowmember 102 is connectable to the radio frequency generator 110.

According to yet another embodiment of the present invention theelongated hollow member 102 comprises an insulating sheath that ishollow and surrounds the elongated hollow member 102. The insulatingsheath is electrically insulating and may therefore be used to insulateat least part of the first electrode from the surrounding tissue. Theinsulating sheath surrounding the elongated hollow member 102 isslideably movable in the longitudinal direction of the elongated hollowmember 102. By sliding the insulating sheath along the elongated hollowmember 102 over the first electrode, variation of the length of thefirst electrode is enabled. The effective length of the first electrodecan thus be varied without moving the elongated hollow member in thelongitudinal direction. Also the penetration depth of the firstelectrode in the tissue can be varied without altering the length of thefirst electrode that is subjected to the tissue, due to presence of theinsulating sheath.

Moreover, by letting the slideable insulating sheath at least surroundthe first electrode at the air-skin interface upon operating, anunfavourable skin burn effect can effectively be avoided. The design ofthe slidable sheath may thus be such that a first part is arranged to beinsertable in the tissue surrounding the first electrode and a secondpart is arranged to hinder further penetration of the second part in thetissue. This second part for instance in the form of a flange or acollar is arranged to contact the tissue surface, that is the skin,whereas the first part of the sheath is arranged to penetrate the skinof the tissue, to avoid such a skin burn effect.

According to one alternative of the present invention the firstelectrode may be segmented in the longitudinal direction of theelongated hollow member 102, that is along the elongated hollow member.Upon insertion of such a elongated hollow member having a segmentedfirst electrode, in a tissue, a few of the electrode segments may besurrounded by body tissue, whereas others may still face the surroundingair by being outside of the body tissue, dependent on the insertionlength of the elongated hollow member 102.

Since some electrode segments will be within the body and other willnot, the impedance between the electrode segments of the first electrodeof the elongated hollow member and the counter electrode will vary inrelation to the insertion depth of the elongated hollow member in thetissue. Whereas the impedance between the segments facing air and thecounter electrode is essentially infinite, the impedance between asegment being penetrated in the tissue and the counter electrode willdepend on the surrounding tissue and will typically be less than the onefor the segment facing air.

According to this embodiment the sensing unit 104 senses the number ofelectrode segments that are inserted in the body, and determines theinsertion depth by way of this segment number, wherein each segment mayhave a longitudinal width of approximately 1-20 mm.

According to this embodiment of the present invention the segmentationalso permits the control unit 108 to turn on/off various segments of theelectrode depending for instance on the impedance as an indicator of thepenetration depth of first electrode of the elongated hollow member. Byturning off the segment at the air-skin interface of the elongatedhollow member, skin burn effects can successfully be avoided, whilesimultaneously ensuring complete tract killing. The application of radiofrequency energy may thus be optimized according to different positionsor motions of the elongated hollow member with respect to the tissuesurrounding the electrode.

According to an alternative embodiment of the present invention theelongated hollow member 102 comprises a coating of a dielectric materialat the proximal or distal end, being an electrical insulator at lowradio frequency frequencies for which frequencies the coated part of thefirst electrode cannot conduct electric current. Upon the usage ofhigher frequencies the impedance over the dielectric coating decreases,which enables the usage of the entire needle including the coated part.

In the following a few applications of the present invention aredescribed. It should be mentioned that the principle characteristics andfeatures of the present invention as described above in the detaileddescription of the embodiments are applicable in each one of theapplications that will be described below.

Although the usage of a few features will be repeated in connection withthe specific applications below, this is not intended to preclude theusage of other features are described above, as indicate in the abovestanding paragraph.

According to one preferred embodiment of the present invention, thearrangement 100 is arranged to be used in connection with fine needleaspiration (FNA). Within this application the anti-seeding technique isincorporated in an aspiration needle, being one example of an elongatedhollow member 102, enabling the aspiration of aspirate of suspectedtumour cells without the risk of seeding malignant cells and infectiousmatter upon both withdrawal and insertion of the aspiration needle inthe needle track.

In the following, a FNA arrangement comprising anti-seeding featureswill be described in some detail.

According to one embodiment of the present invention the arrangement 100comprises a tubular needle 102, being another example of an elongatedhollow member.

The FNA needle to be inserted into the sampling site of the human oranimal body, typically comprises a tubular member with a sharp distalend. According to one embodiment, the needle has an external diameter inthe range of up to 3 mm and a length of 15-150 mm, depending on thetumour or sampling site.

The needle may furthermore comprise a first electrode positioned alongthe needle from the distal end of the needle until a region near theproximal end of the needle, which proximal end of the needle iselectrically isolated from the radio frequency source.

If the needle is made of metal the exterior needle surface is preferablyprovided with an insulating or a dielectric material surrounding theneedle near the proximal end of the needle, such that skin damage of theskin in direct contact with the needle, due to the heat of the needleupon application, can be effectively avoided. If dielectric material isused, impedance measurements to determine penetration depth variationscan still be used.

As discussed above provision of alternatives such as a slidableinsulating sheath or a segmented electrode can also be applied to avoidskin damage, with the advantage that the penetration depth can be variedwith complete denaturation of the entire needle tract.

As earlier determined by the inventor facilitated punctuation ofun-healthy tissue and an increased amount of aspirate may be achievedwhen applying a longitudinal motion and rotational motion to theaspiration needle. This motion inserts and retracts the needleperiodically when being applied to the needle.

In order to avoid spreading of malignant tumour cells and infectiousmatter when for instance inserting/retracting the aspiration needle intoa tissue that is healthy, a solution comprising the application of radiofrequency energy is thus proposed.

According to another preferred embodiment of the present invention thearrangement 100 is an anti-seeding arrangement that is adapted forinfusion of diagnostic or therapeutic substances. The infusion needlemay in all other aspects be the same as the fine needle aspirationneedle, as described above.

According to another preferred embodiment of the present invention thearrangement is an anti-seeding arrangement that is adapted for corebiopsy. Within this application the anti-seeding technique isincorporated in a biopsy needle, being one example of the elongatedhollow member, enabling the removal of a core biopsy of suspected tumourcells without the risk of seeding malignant cells or infectious matterin the needle track.

The core biopsy needle may comprise a tubular member and a solid memberprovided inside said tubular member having an outer diameter of up to3.5 mm and length of 50-150 mm depending on the tumour site, accordingto one embodiment of the present invention. An outer diameter up to 4.5mm and a length of 30-200 mm may however also be provided, according toan alternative embodiment. The solid member may be provided with astorage compartment at the distal end for the core biopsy sample. Duringsampling the tubular member is slid over the solid member, usually underspring load or the like, to cut off tissue material in the storagecompartment.

According to one core biopsy embodiment, the solid member may beelectrically connected to the tubular member, enabling anti-seedingproperties of also the solid member.

Further, the gathering of tissue is often completed within a fraction ofa second, for the reason of the tubular and solid member being springloaded in relation to each other. Both of these aspects, periodiclongitudinal motion and rapid tissue gathering, require a rapidanti-seeding procedure. In order to achieve an appropriate anti-seedinga triggered procedure comprising pulsed energy delivery is required, forwhich reason it is provided by the present invention.

In addition to the advantage of denaturing possible cancer cells andinfectious matter in the needle track, application of radio frequencyenergy brings the advantage of stopping potential bleeding from thebiopsy needle track, which becomes an even more important feature whenusing relatively coarse needles.

As explained above, embodiments comprising a slidable insulating sheathmay be successfully applied in connection with core biopsy to avoid skinburn effects and to enable the optimizing the effective length of thefirst electrode.

According to yet another embodiment of the present invention a segmentedelectrode may also be used in connection to this application being corebiopsy of the present invention, according to lines as stated above.

According to yet another embodiment of the present invention adielectric coating may also be used in connection to this applicationbeing core biopsy of the present invention, according to lines as statedabove.

According to another preferred embodiment of the present invention, theanti-seeding arrangement is arranged for treatment with radio frequencyablation of for instance malignant tissue. Within this embodiment of thepresent invention the elongated hollow member comprises a treatmentablation needle.

In one example of such a treatment ablation needle it comprises twoparallel internal channels that are connected to each other near or atthe distal end of the needle, for enabling a cooling media to flowthrough the channel to enable temperature regulation of the ablationneedle.

The ablation needle further comprises a first electrode that accordingto a preferred embodiment is longitudinally sectioned in two parts. Thisenables optimization of the distal section for tumour ablation treatmentwhereas both parts may be activated during anti-seeding.

According to an alternative embodiment of the present invention theablation needle is coated at the proximal or distal end with adielectric material, being an electrical insulator at low radiofrequency frequencies for which frequencies the coated part of the firstelectrode cannot conduct electric current to for example avoid tissuedamage. Upon the usage of higher frequencies the impedance over thedielectric coating decreases, which enables the usage of the entireneedle including the coated part for denaturising or impedance measuringpurposes of the needle tract.

According to an alternative embodiment of the present invention, theablation needle comprises a movable isolation sheath which may be slidin the longitudinal direction of the tubular needle 102 which results ina variation of the electrode length of the tubular needle 102. Theseembodiments thus enable optimization of the electrode length for boththe ablation treatment and the anti-seeding procedure.

According to yet another embodiment the ablation needle comprises anelectrode being sectioned in more than two electrodes.

Within the embodiments of the present invention as described above, theslidable sheath being used for skin burn protection, can be placed ontothe skin surface by making use of, for example, a larger diameter of theproximal end in the form of a flange or a collar of the tubular member,enabling penetration depth measurements by measuring impedance.

According to an alternative embodiment of the present invention, thearrangement adapted for radio frequency ablation comprises numeroustreatment electrodes which can be extended from the tubular member in anumbrella like configuration during the ablation treatment phase. Such anarrangement can be considered to comprise one treatment section of theextendable umbrella electrodes, whereas anti-seeding is applied to theentire tubular member, except for the proximal end of the member,optionally being electrically isolated from the radio frequency source.

According to another preferred embodiment of the present invention thearrangement is an anti-seeding arrangement that is adapted for minimallyinvasive surgery, inspection and sampling such as for example forendoscopic procedures.

During minimally invasive surgery or laparoscopy several tubular membersin the form of trocars may be inserted from incisions and/or bodyopenings of the patient. The trocars are typically used for inserting acamera, surgical instruments, illumination etc. into the site.Especially during excision of tumours the risk of tumour spread in thetrocar ports is substantial.

The first electrode may for this reason be positioned along the tubularmember as was described in connection to the fine needle aspirationembodiment. The surgical instruments that may be inserted in the trocarcan optionally be electrically connected to the tubular member to enableanti-seeding if appropriate. The relative penetration depth between thetrocar and the inserted instrument may be determined by measuring theimpedance, or by mechanically, electromagnetically or acousticallydetermining the penetration distance.

During robot endoscopy the anti-seeding technique can be implemented forthe tubular members of the stereo tactical excision system of the robot.By penetration depth measurements triggering of anti-seeding pulsing maybe accomplished.

Application of slidable insulating sheaths may be used for thisapplication also, bringing the same or similar advantageous as describedabove in connection to the other applications of the present invention.

The usage of segmented and coated electrodes may likewise be used forminimally invasive surgery, offering advantageous effects similar to theones as described above.

The described present invention thus carries the following advantages:

Upon applying pulsed radio frequency bursts for anti-seeding of thetracks formed, the denaturation of cells occurs within a layer havingthe thickness of the order of a few cell layers surrounding theelongated tubular member. This is an advantage since it is desired notto affect cells outside of the track formed.

Another advantage is that the radio frequency bursts stop potentialbleeding by denaturating the cells in the layer surrounding theelongated tubular member.

Yet another advantage is that the thickness of the layer to be denaturedmay be altered by using different power and pulse settings. It isfurther advantageous that the cell denaturation may be performedautomatically, that is without manual intervention, and instantaneously,which results in minor tissue disturbances as compared to the usage ofthe equipment as disclosed in the prior art.

It is also advantageous that the radio frequency pulsing technique isable to denaturise the needle tract instantaneously during very fastinstrument movements for example when using a spring loaded biopsyexcision instrument or when using longitudinal vibration to decreasepenetration resistance.

Still yet another advantage is that the automatic triggering enablesdenaturing of multiple tracts that may be created during insertion.

Still yet another advantage is that this invention enables denaturationof the whole track length.

Still yet another advantage is that this invention enables denaturationof infectious matter during insertion for example in transrectalprocedures.

Another clear advantage is that the use of pulsed radio frequency energyresults in the absence of substantial alteration of the sample in thetubular member, within the diagnostic embodiments of the presentinvention.

Application of sensing means for the detection of movement of theelongated hollow member together with the usage of radio frequency powercreating an essentially instantaneous denaturation of tissue surroundingan anti-seeding electrode, provides a rapid arrangement for anti-seedingwithout being directed towards time consuming alternatives as presentedby the prior art.

It is emphasized that this invention can be varied in many ways, ofwhich the alternative embodiments above only are examples of a few.These different embodiments are hence non-limiting examples. The scopeof the present invention, however, is only limited by the subsequentlyfollowing claims.

1-21. (canceled)
 22. An arrangement adapted to avoid seeding infectiouscells during invasive medical procedures on a human body or an animalbody, the arrangement comprising: an electromagnetic field generator; anelongated hollow member having two ends and an electrode, the electrodepositioned such that one portion of the electrode is at one of the twoends of the elongated hollow member, the electrode being connected tothe electromagnetic field generator, the elongated hollow member beingconfigured to be inserted into a human body or an animal body; a sensingunit configured to sense a penetration depth of the elongated hollowmember in tissue; and a control unit arranged to control theelectromagnetic field generator so as to deliver radio frequency (“RF”)energy bursts to the electrode and being arranged to receive the sensedpenetration depth from the sensing unit and control the electromagneticfield generator in dependence on the sensed penetration depth andcomprising a triggering unit arranged to trigger the electromagneticfield generator to deliver RF energy bursts in dependence on variationsof the sensed penetration depth of the elongated hollow member.
 23. Thearrangement according to claim 22, wherein the elongated hollow membercomprises a region that is electrically insulated in relation to theelectrode.
 24. The arrangement according to claim 23, wherein theinsulated region comprises a hollow insulating sheath beinglongitudinally movable along the elongated hollow member over theelectrode, whereby the effective length of the electrode can be variedwithout moving the elongated hollow member longitudinally.
 25. Thearrangement according to claim 23, wherein the insulating regioncomprises a hollow insulating sheath being longitudinally movable alongthe elongated hollow member over the electrode, the hollow insulatingsheath having a first part arranged to be insertable in tissuesurrounding the electrode, and a second part arranged to hinder furtherpenetration of the second part into tissue, the second part comprising aflange.
 26. The arrangement according to claim 22, wherein the electrodeis longitudinally segmented with each segment individually controlled bythe control unit wherein the control unit is arranged to control thetriggering unit to trigger the electromagnetic field generator todeliver bursts of radio frequency (RF) energy to selected segments ofthe electrode, wherein a segment of the electrode that is positioned atan air-skin interface of the elongated hollow member can be deactivatedwhereby skin burn effects can be avoided.
 27. The arrangement accordingto claim 22, wherein the elongated hollow member comprises a pluralityof electrodes each of which is individually controllable by the controlmeans wherein the control means is arranged to control the triggeringunit to trigger the electromagnetic field generator to deliver bursts ofradio frequency (RF) energy to selected electrodes of the plurality ofelectrodes of the elongated hollow member.
 28. The arrangement accordingto claim 22, wherein the elongated hollow member is coated with adielectric material whereby the frequency of operation of the electrodeis limited to higher frequencies.
 29. The arrangement according to claim22, wherein the control means is further arranged to automaticallycontrol the triggering unit to trigger the electromagnetic fieldgenerator to deliver bursts of radio frequency (RF) energy to theelectrode of the elongated hollow member when the sensing unitdetermines that movement of the elongated hollow member is occurring.30. The arrangement according to claim 22 wherein a burst of energyprovided by the electromagnetic field generator comprises energy havingan off-duration that is several orders of magnitude larger than anon-duration of the energy.
 31. An arrangement adapted to avoid seedinginfectious cells during invasive medical procedures on a human body oran animal body, the arrangement comprising: an electromagnetic fieldgenerator; an elongated hollow member having two ends and an electrode,the electrode positioned such that one portion of the electrode is atone of the two ends of the elongated hollow member, the electrode beingconnected to the electromagnetic field generator, the elongated hollowmember being configured to be inserted into a human body or an animalbody, the hollow member further comprising a hollow insulating sheathbeing longitudinally movable over the electrode to selectively surroundthe electrode thereby creating an insulating region; a sensing unitconfigured to sense an effective penetration depth of the elongatedhollow member in tissue, the effective penetration depth being varied independence on the movement of the hollow insulating sheath along theelongated hollow member; and a control unit arranged to receive thesensed effective penetration depth from the sensing unit and control theelectromagnetic field generator to deliver radio frequency (“RF”) energybursts to the electrode, and being arranged to control theelectromagnetic field generator in dependence on the sensed penetrationdepth, and comprising a triggering unit arranged to trigger theelectromagnetic field generator to deliver RF energy bursts independence on variations of the sensed effective penetration depth ofthe elongated hollow member.
 32. The arrangement according to claim 31,wherein the hollow insulating sheath has a first part arranged to beinsertable in tissue surrounding the electrode, and a second partarranged to hinder further penetration of the second part into tissue,the second part comprising a flange.
 33. The arrangement according toclaim 31, wherein the electrode is longitudinally segmented with eachsegment individually controlled by the control unit wherein the controlunit is arranged to control the triggering unit to trigger theelectromagnetic field generator to deliver bursts of radio frequency(RF) energy to selected segments of the electrode, wherein a segment ofthe electrode that is positioned at an air-skin interface of theelongated hollow member can be deactivated whereby skin burn effects canbe avoided.
 34. The arrangement according to claim 31, wherein theelongated hollow member comprises a plurality of electrodes each ofwhich is individually controllable by the control means wherein thecontrol means is arranged to control the triggering unit to trigger theelectromagnetic field generator to deliver bursts of radio frequency(RF) energy to selected electrodes of the plurality of electrodes of theelongated hollow member.
 35. The arrangement according to claim 31,wherein the elongated hollow member is coated with a dielectric materialwhereby the frequency of operation of the electrode is limited to higherfrequencies.
 36. The arrangement according to claim 31, wherein thecontrol means is further arranged to automatically control thetriggering unit to trigger the electromagnetic field generator todeliver bursts of radio frequency (RF) energy to the electrode of theelongated hollow member when the sensing unit determines that movementof the elongated hollow member is occurring.
 37. The arrangementaccording to claim 31 wherein a burst of energy provided by theelectromagnetic field generator comprises energy having an off-durationthat is several orders of magnitude larger than an on-duration of theenergy.
 38. A method for avoiding the seeding of infectious cells duringan invasive medical procedure on a human body or an animal body, themethod comprising: sensing a penetration depth in tissue of an elongatedhollow member having two ends and an electrode, the electrode positionedsuch that one portion of the electrode is at one of the two ends of theelongated hollow member, the electrode being connected to anelectromagnetic field generator; and controlling the electromagneticfield generator to deliver radio frequency (“RF”) energy bursts to theelectrode in dependence on the sensed penetration depth of the hollowmember and triggering the electromagnetic field generator to deliver RFenergy bursts in dependence on variations of the sensed penetrationdepth of the elongated hollow member.
 39. The method according to claim38, further comprising the step of moving longitudinally a hollowinsulating sheath along the elongated hollow member over the electrodewherein the elongated hollow member comprises a region that iselectrically insulated in relation to the electrode, and whereby theeffective length of the electrode can be varied without moving theelongated hollow member longitudinally.
 40. The method according toclaim 39, further comprising the step of hindering insertion of thesecond part of the hollow sheath member into tissue by means of a flangeassociated with a second part of the hollow member.
 41. The methodaccording to claim 38, wherein the step of sensing further comprisessensing a penetration depth in tissue of an elongated hollow memberhaving a segmented electrode; and the step of controlling furthercomprises triggering the electromagnetic field generator to deliverbursts of radio frequency (RF) energy to selected segments of theelectrode, wherein a segment of the electrode that is positioned at anair-skin interface of the elongated hollow member can be deactivatedwhereby skin burn effects can be avoided.
 42. The method according toclaim 38, wherein the step of sensing further comprises sensing apenetration depth in tissue of an elongated hollow member having aplurality of electrodes; and the step of controlling further comprisestriggering the electromagnetic field generator to deliver bursts ofradio frequency (RF) energy to selected electrodes of the plurality ofelectrodes located in the elongated hollow member, wherein each of theelectrodes is individually controllable.
 43. The method according toclaim 38, wherein the step of controlling further comprisesautomatically triggering the electromagnetic field generator to deliverbursts of radio frequency (RF) energy to the electrode of the elongatedhollow member upon sensing that movement of the elongated hollow memberis occurring.
 44. The method according to claim 38, wherein the step ofcontrolling further comprises controlling the electromagnetic fieldgenerator to deliver radio frequency (“RF”) energy bursts having anoff-duration that is several orders of magnitude larger than anon-duration of the energy.